Fragrance chemicals are used in numerous products to enhance the consumer's enjoyment of a product. Fragrance chemicals are added to consumer products such as laundry detergents, fabric softeners, soaps, detergents, personal care products, such as but not limited to shampoos, body washes, deodorants and the like, as well as numerous other products.
In order to enhance the effectiveness of the fragrance materials for the user, various technologies have been employed to enhance the delivery of the fragrance materials at the desired time. One widely used technology is encapsulation of the fragrance material in a protective coating. Frequently the protective coating is a polymeric material. The polymeric material is used to protect the fragrance material from evaporation, reaction, oxidation or otherwise dissipating prior to use. A brief overview of polymeric encapsulated fragrance materials is disclosed in U.S. Pat. No. 4,081,384, which describes a softener or anti-stat core coated by a polycondensate suitable for use in a fabric conditioner; U.S. Pat. No. 5,112,688, which discloses selected fragrance materials having the proper volatility to be coated by coacervation with micro particles in a wall that can be activated for use in fabric conditioning; U.S. Pat. No. 5,145,842, which describes a solid core of a fatty alcohol, ester, or other solid plus a fragrance coated by an aminoplast shell; and U.S. Pat. No. 6,248,703, which describes various agents including fragrance in an aminoplast shell that is included in an extruded bar soap.
While encapsulation of fragrance in a polymeric shell can help prevent fragrance degradation and loss, it is often not sufficient to significantly improve fragrance performance in consumer products. Therefore, methods of aiding the deposition of encapsulated fragrances have been described. U.S. Pat. No. 4,234,627 discloses a liquid fragrance coated with an aminoplast shell further coated by a water insoluble meltable cationic coating in order to improve the deposition of capsules from fabric conditioners. U.S. Pat. No. 6,194,375 discloses the use of hydrolyzed polyvinyl alcohol to aid deposition of fragrance-polymer particles from wash products. U.S. Pat. No. 6,329,057 discloses the use of materials having free hydroxy groups or pendant cationic groups to aid in the deposition of fragranced solid particles from consumer products.
In addition, the use of silica to form microcapsule formulations specifically designed to prevent an encapsulated active ingredient from leaving the microcapsule has been described. This is desirable when the active ingredient is an irritant to the body tissue to which it is applied. It is also is desired when the active ingredient acts by interaction with light, such as sunlight. However, U.S. Pat. No. 6,303,149 fails to disclose compositions and methods for releasing and hence delivering the active ingredients. Despite these and many other disclosures there is an ongoing need for the improved delivery of fragrance materials for various personal care products, rinse-off products and leave-on products that provide improved performance.